Overview

Smoothly varying sine wave generator

Discussion

Sine wave generator, with parameters for controling frequency and start phase. This is a source module and requires that you specify the properties of the output pin (number of channels, blockSize, and sample rate) at construction time. The smoothing coefficient allows for changes to the frequency parameter to be exponentially smoothed (first order IIR) at the sample rate.

Internally, this modules uses the sin() function from the C math library . The instantaneous frequency (which is the phase increment between samples) is smoothed on a sample by sample basis. If you do not need smoothed behavior, use the more efficient sine_gen_module.m instead.

Type Definition

typedef struct _ModuleSineSmoothedGenFract32
{
    ModuleInstanceDescriptor instance;            // Common Audio Weaver module instance structure
    FLOAT32 freq;                                 // Frequency of the sine wave, in Hz.
    FLOAT32 smoothingTime;                        // Time constant of the frequency adjustment operation, in msec.
    FLOAT32 startPhase;                           // Starting phase of the sine wave, in degrees.
    fract32 smoothingCoeff;                       // Smoothing coefficient
    fract32 phase;                                // Instantanteous phase and also starting phase
    fract32 phaseIncTarget;                       // Target for the sample to sample phase increment. Essentially the target frequency
    fract32 phaseInc;                             // Instantaneous sample to sample phase increment
} ModuleSineSmoothedGenFract32Class;

Variables

Properties

Name	Type	Usage	isHidden	Default value	Range	Units
freq	float	parameter	0	1000	0.01:24000	Hz
smoothingTime	float	parameter	0	10	0:1000	msec
startPhase	float	parameter	0	0	0:360	degrees
smoothingCoeff	fract32	derived	1	0.002081	Unrestricted
phase	fract32	derived	1	0	Unrestricted	radians
phaseIncTarget	fract32	derived	1	0.01636	Unrestricted	radians/sample
phaseInc	fract32	derived	1	0.01636	Unrestricted	radians/sample

Pins

Output Pins

Name: out

Description: audio output

Data type: float

MATLAB Usage

File Name: sine_smoothed_gen_fract32_module.m

 M=sine_smoothed_gen_fract32_module(NAME, SR, BLOCKSIZE)
 Creates a sine wave generator for use in the Audio Weaver.  This
 module has a single 1 channel output pin with controllable frequency
 and built in frequency smoothing.  Arguments:
    NAME - name of the module.
    SR - sample rate
    BLOCKSIZE - number of samples per output channel.